include[HTML_REMOVED]

include[HTML_REMOVED]

include[HTML_REMOVED]

using namespace std;

int f(int n){
if(n==1)return 1;
if(n==2)return 2;
return f(n-1)+f(n-2);
}

int main(){
int n;
cin>>n;
cout<<f(n)<<endl;
return 0;

}